1. Field of the Invention
The present invention relates to a rear conversion lens which is mounted on the image side of an objective lens to magnify an image formed by the objective lens and more particularly to a smaller rear conversion lens (teleconverter) capable of achieving image stabilization.
2. Related Background Art
In a single objective lens such as a photographic lens, as its focal length becomes larger, its shape becomes larger in accordance with the focal length and its manufacturing cost becomes high. Therefore, it is difficult to make a camera have a plurality of objective lenses having comparatively large different focal lengths.
A rear conversion lens is a comparatively small and inexpensive additional optical system to be mounted on the image side of an objective lens. As the rear conversion lens can easily magnify the focal length of the objective lens 1.6 times or the like, it is advantageous to utilize the rear conversion lens in terms of portability and cost.
However, in general, the rear conversion lens magnifies not only the focal length of the objective lens but also aberrations thereof, so aberration correction becomes very complicated. Also, as the focal length is magnified, the angle of view is narrowed, which easily causes deterioration of an image due to a shake of hands, vibration and so on.
In such a rear conversion lens, the above-mentioned aberration correction and image stabilization (a correction of a change of an image condition due to a shake of hands, vibration and so on) have not been performed sufficiently.